U.S. patent application number 13/709869 was filed with the patent office on 2013-06-20 for tester apparatus for obtaining forming limit diagram.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Yong Kyun Cho, Jun Beom Lee, Ki Ju NAM.
Application Number | 20130152706 13/709869 |
Document ID | / |
Family ID | 48586298 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130152706 |
Kind Code |
A1 |
NAM; Ki Ju ; et al. |
June 20, 2013 |
TESTER APPARATUS FOR OBTAINING FORMING LIMIT DIAGRAM
Abstract
A tester apparatus capable of obtaining a forming limit diagram
pertaining to a sample having a high degree of precision includes a
fixing jig and a mobile jig installed at an upper side of the
fixing jig so as to enable a vertical movement. The mobile jig may
be configured to fix the sample in cooperation with the fixing jig,
and a driving apparatus disposed at a lower side of the fixing jig
may be configured to drive the vertical movement of the mobile jig.
An interlocking apparatus provided in between the mobile jig and
the driving apparatus may be configured to deliver a driving force
of the driving apparatus to the mobile jig.
Inventors: |
NAM; Ki Ju; (Suwon-si,
KR) ; Lee; Jun Beom; (Suwon-si, KR) ; Cho;
Yong Kyun; (Suwon-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD.; |
Suwon-si |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
48586298 |
Appl. No.: |
13/709869 |
Filed: |
December 10, 2012 |
Current U.S.
Class: |
73/863.11 ;
73/864.91 |
Current CPC
Class: |
G01N 3/08 20130101; G06F
30/17 20200101; G01N 3/04 20130101; Y02T 10/82 20130101; B21D 22/02
20130101; G06F 2113/22 20200101 |
Class at
Publication: |
73/863.11 ;
73/864.91 |
International
Class: |
G06F 17/50 20060101
G06F017/50 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2011 |
KR |
10-2011-0135311 |
Claims
1. A tester apparatus for obtaining a forming limit diagram, the
tester apparatus comprising: a fixing jig configured to accommodate
a sample on an upper surface of the fixing jig; a mobile jig
installed adjacent to an upper side of the fixing jig which is
configured to move in a vertical direction and configured to fix
the sample in cooperation with the fixing jig, when a sample is
placed on the fixing jig; a driving apparatus disposed at a lower
side of the fixing jig configured to drive the vertical movement of
the mobile jig; and an interlocking apparatus provided in between
the mobile jig and the driving apparatus configured to deliver a
driving force of the driving apparatus to the mobile jig.
2. The tester apparatus of claim 1, wherein: the interlocking
apparatus comprises a driving plate configured to be driven by the
driving apparatus, and a plurality of connecting rods coupled in
between the driving plate and the mobile jig, disposed in a
parallel manner.
3. The tester apparatus of claim 2, wherein the fixing jig includes
a plurality of penetrating holes through which the plurality of
connecting rods respectively penetrate to connect to the mobile
jig.
4. The tester apparatus of claim 1, wherein: a heater is installed
at the fixing jig to heat the fixing jig.
5. The tester apparatus of claim 1, wherein: a heater is installed
at the mobile jig to heat the mobile jig.
6. The tester apparatus of claim 1, further comprising: a punch
installed at an upper side of the mobile jig which is configured to
move in a vertical direction to perform a forming on the
sample.
7. The tester apparatus of claim 6, further comprising: a guide rod
which extends downward from a lower surface of the punch; and a
guider provided at the mobile jig to guide forward and backward
vertical movements of the guide rod.
8. The tester apparatus of claim 6, wherein the mobile jig and
fixing jig each include a processing hole to provide a space for
the punch to penetrate through the mobile jig and the fixing
jig.
9. The tester apparatus of claim 8, wherein: a fixing protrusion,
which is configured to fix the sample, and a fixing groove, which
corresponds to the fixing protrusion, are disposed adjacent to the
processing hole.
10. The tester apparatus of claim 6, wherein: a measurement
apparatus is installed at an upper portion of the punch to measure
a load applied to the sample by the punch.
11. The tester apparatus of claim 6, wherein: a temperature
controlling apparatus is installed at the punch.
12. The tester apparatus of claim 1, further comprising: a camera
unit disposed at a lower side of the fixing jig to observe the
sample.
13. The tester apparatus of claim 1, wherein: the driving apparatus
comprises at least one of a hydraulic cylinder or an electric
motor.
14. A tester apparatus for obtaining a forming limit diagram, the
tester apparatus comprising: a fixing jig; a mobile jig disposed at
an upper side of the fixing jig and configured to move in a
vertical direction with respect to the fixing jig; and a heater
installed in between the fixing jig and the mobile jig to heat the
fixing jig and the mobile jig.
15. The tester apparatus of claim 14, wherein the heater installed
in between the fixing jig and the mobile jig includes a high
frequency heating coil.
16. The tester apparatus of claim 14, wherein a plurality of
heaters are internally disposed horizontally in at least one of the
fixing jig and the mobile jig.
17. The tester apparatus of claim 15, further comprising a
radiation panel disposed at a lower surface of the fixing jig to
prevent heat transfer to a lower side of the fixing jig.
18. A method of performing a forming limit diagram test on a sample
using a tester apparatus the method comprising: selectively
activating a heating element according to whether a hot rolling or
a cold rolling is performed, the heating element being disposed
between a fixing jig configured to accommodate the sample on an
upper surface of the fixing jig, and a vertically adjustable mobile
jig disposed adjacent to the upper surface of the fixing jig;
selectively activating at least one heater disposed internally in
at least one of the fixing jig and the mobile jig, according to
whether a hot rolling or a cold rolling is performed; lowering the
mobile jig to fix the sample between the mobile jig and the fixing
jig, by operating a driving apparatus to drive a vertical movement
of the mobile jig; lowering a punch installed at an upper side of
the mobile jig to perform a forming on the sample; and terminating
the lowering of the punch when the sample fractures.
19. The method of claim 18, further comprising controlling a
temperature of the punch to maintain a temperature of the punch
between about -20.degree. C. to about 20.degree. C.
20. The method of claim 18, wherein if a hot rolling is performed,
the at least one heater is activated to preheat at least one of the
mobile jig and the fixing jig to a predetermined temperature,
before the lowering of the mobile jig.
21. The method of claim 20, wherein the at least one of the mobile
jig and the fixing jig is preheated to about 200.degree. C. before
the lowering of the mobile jig.
22. The method of claim 18, wherein if a hot rolling is performed,
the sample is heated to a predetermined temperature before the
lowering of the mobile jig.
23. The method of claim 22, wherein the sample is heated to a
predetermined temperature at or above about 900.degree. C. before
the lowering of the mobile jig.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of Korean
Patent Application No. 10-2011-0135311, filed on Dec. 15, 2011, in
the Korean Intellectual Property Office, the disclosure of which is
incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] Embodiments disclosed herein relate to a tester apparatus
for obtaining a forming limit diagram from basic physical
properties of a sample which is a forming material.
[0004] 2. Description of the Related Art
[0005] Recently, when developing a product, CAM (Computer Aided
Manufacturing) applications in mold design are increasingly used to
reduce a production time of the product and to respond to the
diversification of the product lineups.
[0006] CAM applications in mold design may be used during the
production process of a product and enable the confirmation and the
modification of a process result prior to the production of a
product. Additionally, when changing the design of a product, CAM
applications enable a product to be improved effectively and
efficiently by saving time and reducing costs.
[0007] In order to obtain a superior result by use of CAM
applications when designing a product, physical properties and
characteristics of the forming material used in molding design need
to be obtained beforehand. In general, basic tests which are used
to obtain the properties of a pressed metallic panel include a
tensile test, a FLD (Forming Limit Diagram) test, and a friction
coefficient assessment test. Among the above-mentioned tests, the
FLD test is considered as an important tool in determining the
forming limit of a panel. However, if the FLD test is conducted in
a general press facility without having an exclusive test apparatus
configured to obtain the forming limit diagram, due to the
characteristics of the press facility, a precise control of a
stroke may be difficult, and thus the degree of precision of the
test may be reduced.
[0008] Particularly, as the introduction of hot press forming is
increasingly being used, the high-temperature forming limit diagram
may be needed to be obtained, and thus a need exists for developing
an exclusive test apparatus configured to obtain a hot forming
limit diagram, in addition to a cold forming limit diagram, which
may be used to derive the physical properties and characteristics
of the forming material used in molding design, and used by CAM
applications.
SUMMARY
[0009] Therefore, it is an aspect of the present disclosure to
provide a tester apparatus for obtaining a forming limit diagram
capable of obtaining the forming limit diagram having a high degree
of precision.
[0010] It is another aspect of the present disclosure to provide a
tester apparatus for obtaining a forming limit diagram capable of
obtaining a hot forming limit diagram in addition to a cold forming
limit diagram.
[0011] Additional aspects of the disclosure will be set forth in
part in the description which follows and, in part, will be
apparent from the description, or may be learned by practice of the
disclosure.
[0012] In accordance with one aspect of the present disclosure, a
tester apparatus includes a fixing jig, a mobile jig, a driving
apparatus and an interlocking apparatus. The fixing jig allows a
sample to be placed thereon. The mobile jig may be installed at an
upper side of the fixing jig so as to enable a vertical movement
and may be configured to fix the sample in cooperation with the
fixing jig. The driving apparatus may be disposed at a lower side
of the fixing jig and may be configured to drive the vertical
movement of the mobile jig. The interlocking apparatus may be
provided in between the mobile jig and the driving apparatus and
configured to deliver a driving force of the driving apparatus to
the mobile jig.
[0013] The interlocking apparatus may include a driving plate
configured to be driven by the driving apparatus, and a plurality
of connecting rods coupled in between the driving plate and the
mobile jig and disposed in a parallel manner.
[0014] A penetrating hole may be provided at the fixing jig so that
the connecting rod penetrates the fixing jig.
[0015] A heater may be installed at the fixing jig to heat the
fixing jig.
[0016] A heater may be installed at the mobile jig to heat the
mobile jig.
[0017] The tester apparatus may further include a punch installed
at an upper side of the mobile jig in a movable manner in a
vertical direction to perform a forming on the sample.
[0018] A guide rod may be formed at a lower surface of the punch
and a guider may be provided at the mobile jig to guide forward and
backward movements of the guide rod.
[0019] A processing hole may be provided at each of the mobile jig
and the fixing jig so that the punch penetrates through the mobile
jig and the fixing jig.
[0020] A fixing protrusion, which is configured to fix the sample,
and a fixing groove, which corresponds to the fixing protrusion,
may be provided at surroundings of the processing hole.
[0021] A measurement apparatus may be installed at an upper portion
of the punch to measure a load applied to the sample by the
punch.
[0022] A temperature controlling apparatus may be installed at the
punch.
[0023] The tester apparatus may further include a camera unit
disposed at a lower side of the fixing jig for an observation of
the sample.
[0024] The driving apparatus may include a hydraulic cylinder or an
electric motor.
[0025] In accordance with another aspect of the preset disclosure,
a tester apparatus for obtaining a forming limit diagram includes a
fixing jig, a mobile jig, and a heater. The mobile jig may be
disposed at an upper side of the fixing jig and provided in a
movable manner in a vertical direction with respect to the fixing
jig. The heater may be installed in between the fixing jig and the
mobile jig for the heating of the fixing jig and the mobile jig
and/or the sample.
[0026] The heater installed in between the fixing jig and the
mobile jig may include a high frequency heating coil. A plurality
of heaters may also be internally disposed horizontally in at least
one of the fixing jig and the mobile jig. A radiation panel may
further be disposed at a lower surface of the fixing jig to prevent
heat transfer to a lower side of the fixing jig.
[0027] In accordance with another aspect of the present disclosure,
a method for performing a forming limit diagram test on a sample
using a tester apparatus may include: selectively activating a
heating element disposed between a fixing jig configured to
accommodate the sample on an upper surface thereof and a mobile jig
disposed adjacent to the upper surface of the fixing jig, according
to whether a hot rolling or a cold rolling is performed;
selectively activating at least one heater disposed internally in
at least one of the fixing jig and the mobile jig, according to
whether a hot rolling or a cold rolling is performed; lowering the
mobile jig to fix the sample between the mobile jig and the fixing
jig by operating a driving apparatus to drive a vertical movement
of the mobile jig; lowering a punch installed at an upper side of
the mobile jig to perform a forming on the sample; and terminating
the lowering of the punch when the sample fractures.
[0028] The method for performing a forming limit diagram test on a
sample may further include controlling a temperature of the punch
to maintain a temperature of the punch between about -20.degree. C.
to about 20.degree. C.
[0029] If a hot rolling is performed, the heating element may be
activated to heat the sample to a predetermined temperature. For
example, the sample may be heated to at or above about 900.degree.
C. If a hot rolling is performed the at least one heater may be
activated to preheat at least one of the mobile jig and the fixing
jig to a predetermined temperature, before the lowering of the
mobile jig. For example, the at least one of the mobile jig and the
fixing jig may be preheated to about 200.degree. C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] These and/or other aspects of the disclosure will become
apparent and more readily appreciated from the following
description of the embodiments, taken in conjunction with the
accompanying drawings of which:
[0031] FIG. 1 is a cross-sectional view of a tester apparatus for
obtaining a forming limit diagram in accordance with one embodiment
of the present disclosure.
[0032] FIG. 2 is a drawing showing a status of a fixed sample.
[0033] FIG. 3 is a drawing showing a status of a sample during the
beginning of the forming process.
[0034] FIG. 4 is a drawing showing a status of a sample at an
ending of the forming process when a break of the sample
occurs.
[0035] FIG. 5 is a cross-sectional view of a tester apparatus for
obtaining a forming limit diagram in accordance with another
embodiment of the present disclosure.
DETAILED DESCRIPTION
[0036] Reference will now be made in detail to the embodiments of
the present disclosure, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals refer to
like elements throughout.
[0037] As illustrated in FIG. 1, a tester apparatus used to obtain
a forming limit diagram 1 includes a fixing jig 10 and a mobile jig
20 that are configured to fix a sample `S`, a punch 30 configured
to apply pressure and perform a forming on the sample `S`, a
driving apparatus 40 configured to drive the mobile jig 20 to be
moved in a vertical direction, and an interlocking apparatus 50
configured to connect in between the mobile jig 20 and the driving
apparatus 40. The sample `S` may be sheet metal or a other metallic
panel, for example. However, sample `S` may comprise other
materials which may be tested and need not be limited to sheet
metal or metallic panels.
[0038] The fixing jig 10 is formed in a plate type, and a
processing hole 10a may be formed at a central portion of the
fixing jig 10 to form a space through which the sample `S` and the
punch 30 pass when the punch 30 performs a forming on the sample
`S`. A heater 11 may be disposed at an inside of the fixing jig 10
so that when a test to obtain a hot forming limit diagram is to be
conducted, the fixing jig 10 may be pre-heated before a forming is
performed. The heater 11 may be formed with a cartridge heater
having a shape of a bar, and may be installed in an inserted manner
into an installation hole that is formed at the fixing jig 10 in a
horizontal direction. There may be a plurality of installation
holes formed in the fixing jig 10 to accommodate one or more
heaters.
[0039] At a lower side of the fixing jig 10, a main frame 15 is
provided to support the fixing jig 10. The main frame 15 may
include a first base 16, a second base 18, a first supporting
member 17, and a second supporting member 19. The second base 18
may be disposed such that it is spaced apart from the first base 16
in a vertical direction. The first supporting member 17 may support
the first base 16 and the second base 18 by dispersing the weight
applied in between the first base 16 and the second base 18 while
being disposed in a parallel manner in between the first base 16
and the second base 18. The second supporting member 19 may support
the second base 18 and the fixing jig 10 by dispersing the weight
applied in between the second base 18 and the fixing jig 10 while
being disposed in a parallel manner in between the second base 18
and the fixing jig 10.
[0040] At a lower surface of the fixing jig 10, a heat radiation
panel 12 may be installed to prevent heat, which is generated by
the heater 11 internally installed at the fixing jig 10, from being
transferred to a lower side of the fixing jig 10. While FIG. 1
illustrates a heat radiation panel being disposed on a lower
portion of the fixing jig 10 the disclosure is not so limited. For
example, heat radiation panels may be disposed in other locations
of the testing apparatus to prevent heat transfer from the heaters
disposed in the fixing jig and mobile jig. For example, a heat
radiation panel may be disposed on an interior side of the mobile
jig 20 adjacent to processing hole 20a and/or an upper side of the
mobile jig 20, to prevent heat transfer to the punch 30 or to the
guide rod 32, if desired.
[0041] The mobile jig 20 may be disposed at an upper side of the
fixing jig 10, and may be provided in a movable manner in a
vertical direction with respect to the fixing jig 10, so that the
fixing and the separating of the sample `S` may be possible before
and after a forming limit diagram test is conducted with respect to
the sample `S`.
[0042] At the central portion of the mobile jig 20, similar to the
case of the fixing jig 10, a processing hole 20a may be formed to
form a space through which the sample `S` and the punch 30 pass
when the punch performs a forming on the sample `S`. A heater 21
may be internally installed at the mobile jig 20 so that the mobile
jig 20 is pre-heated at a predetermined temperature prior to a
forming limit diagram test being conducted. The heater 21 may be
composed of a cartridge heater, for example. The heater 21 may be
installed in an inserted manner into an installation hole that is
formed at the mobile jig 20 in a horizontal direction. There may be
a plurality of installation holes formed in the mobile jig 20 to
accommodate one or more heaters.
[0043] A fixing protrusion 20b configured to fix the sample `S` may
be provided at a surrounding portion of the processing hole 20a of
the mobile jig 20. That is, the fixing protrusion 20b may be
disposed at a lower surface of the mobile jig 20 adjacent to the
processing hole 20a which is formed in the central portion of the
mobile jig 20. A fixing groove 10b may be provided at a surrounding
portion of the processing hole 10a of the fixing jig 10 such that
the fixing groove 10b is configured to accommodate the fixing
protrusion 20b and a portion of the sample `S` deformed by the
fixing protrusion 20b. That is, the fixing groove 10b may be
disposed at an upper surface of the fixing jig 10 adjacent to the
processing hole 10a which is formed in the central portion of the
fixing jig 10.
[0044] In accordance with the embodiment illustrated, the fixing
protrusion 20b may be provided at the mobile jig 20, and the fixing
groove 10b may be provided at the fixing jig 10. However, the
positions of the fixing protrusion 20b and the fixing groove 10b
may be reversed, so that the protrusion may be provided at the
fixing jig 10 while the fixing groove may be provided at the mobile
jig 20.
[0045] For the forward and backward movements of the mobile jig 20,
at a lower side of the mobile jig 20, the driving apparatus 40 may
be configured to supply the driving force to drive the mobile jig
20, and the interlocking apparatus 50 may be configured to connect
in between the mobile jig 20 and the driving apparatus 40.
[0046] The interlocking apparatus 50 may include a driving plate 51
configured to be driven by the driving apparatus 40, and a
plurality of connecting rods 52 may be connected in between the
driving plate 51 and the mobile jig 20.
[0047] One end of the connecting rod 52 may be coupled to a lower
portion of the mobile jig 20, while the other end of the connecting
rod 52 may be coupled to an upper portion of the driving plate 51.
At the fixing jig 10, a penetrating hole 10c is provided so that
the connecting rod 52 may be penetrated therethrough, and by the
penetrating hole 10c, the linear movement in the vertical direction
of the connecting rod 52 is guided. The connecting rod 52 may be
composed in plurality, and may be disposed in parallel in between
the mobile jig 20 and the driving plate 51.
[0048] The driving apparatus 40 may include a hydraulic apparatus
(not shown) and a hydraulic cylinder 41 configured to operate by
being connected to the hydraulic apparatus (not shown). The
hydraulic cylinder 41 may be installed on the first base 16 of the
main frame 15. A piston rod 42 of the hydraulic cylinder 41 may
penetrate through the second base 18, and may be coupled to a lower
portion of the driving plate 51. Thus, when the piston rod 42 is
moved forward and backward in a vertical direction as the piston
rod 42 of the hydraulic cylinder 41 is interlocked with the mobile
jig 20, the mobile jig 20 is correspondingly moved forward and
backward in a vertical direction by the interlocking apparatus
50.
[0049] A punch 30 may be disposed at an upper side of the mobile
jig 20. The punch 30 may be configured to pressurize the sample `S`
to perform a forming on the sample `S`.
[0050] Meanwhile, the tester apparatus for obtaining a forming
limit diagram 1 in accordance with the present disclosure may be
used to control a stroke of the punch 30, and may be applied for
use as a commercialized test apparatus for a general use, such as a
MTS (Material Test System).
[0051] Thus, a fixed unit M1 of the MTS may be disposed at a lower
portion of the first base 16 to support the first base 16, and a
mobile unit M2 of the MTS may be disposed at an upper portion of
the punch 30 to move the punch 30 in a vertical direction. In
between the mobile unit M2 and the punch 30, a rod cell 31 may be
installed. For example, while the forming of the sample `S` is
performed using the punch 30, the weight that is applied on the
punch by the mobile unit M2 of the MTS may be able to be monitored
by the rod cell 31.
[0052] At one side of the punch 30, a guide rod 32 may be provided
to guide the movement in a vertical direction of the punch 30, and
at the mobile jig 20, a guider 22 to guide the forward and backward
movement of the guide rod 32 may be provided. While FIG. 1
illustrates the guide rod 32 being disposed at one side of the
punch 30 the disclosure is not so limited. For example, the guide
rod 32 may be disposed at the other side of the punch 30 as well.
Alternatively, a guide rod 32 may be provided on both sides of the
punch 30 if desired.
[0053] The guide rod 32 may be formed in a shape of a cylinder, and
at the guider 22, a guide hole 22a may be provided to accommodate
the guide rod 32 while the guide rod 32 is moved forward and
backward.
[0054] At a lower portion of the punch 30, a forming unit 30a
having a semicircular shape may be formed so that the sample `S`
may be formed in a semicircular shape by the punch 30, and a
temperature controlling apparatus 33 may be installed for the
temperature control of the punch 30. The forming unit 30a may have
shapes other than the semicircular shape if desired, for example, a
triangular or rectangular shape.
[0055] At a lower portion of the fixing jig 10, a camera unit 60
may be disposed to monitor the deforming status of the sample `S`
when performing a forming on the sample `S` to obtain a forming
limit diagram.
[0056] The camera unit 60 may be disposed at a central portion of a
lower portion of the processing hole 10a of the fixing jig 10
through the installation bracket 61, which is fixed to the fixing
jig 10, so that the point in time when the break of the sample `S`
occurs may be monitored. Additionally, the camera unit 60 may
record image data by taking a plurality of images which may be used
to obtain the forming limit diagram. The camera unit 60 may include
one or a plurality of cameras to monitor the deforming status of
the sample `S`. While FIG. 1 illustrates the camera unit being
disposed at a central portion of a lower portion of the processing
hole 10a via an installation bracket 61 fixed to a lower surface of
one side of the fixing jig 10 the disclosure is not so limited. For
example, the installation bracket 61 may be fixed to a lower
surface of the other side of the fixing jig 10 as well.
Alternatively, the installation bracket 61 may be fixed to a lower
surfaces of both sides of the fixing jig 10 if desired.
[0057] Hereinafter, referring to FIGS. 1 to 4, a process of
obtaining a forming limit diagram through a tester apparatus for
obtaining a forming limit diagram in accordance with one embodiment
of the present disclosure will be described.
[0058] First, for the test, the sample `S` is prepared. At the
sample `S`, a grid is formed so that the deformation rate of each
portion of the sample `S`, which becomes the basic data for
obtaining a forming limit diagram after the forming is performed by
the punch 30, may be calculated. That is, a predetermined pattern
or lines which make up the grid may be applied to the sample `S`
prior to the forming process. For example, the grid may be composed
of a circular shape or a latticed shape. The grid may be selected
in order to obtain accurate basic data after the forming is
performed by the punch 30. In a case when obtaining a forming limit
diagram at the time of a cold rolling is performed, the grid formed
at the sample `S` may be formed in a printed manner through a
printed medium such as silkscreen. However, in a case when a hot
rolling is performed, heat is needed to be applied with respect to
the sample in the obtaining stage of the forming limit diagram, but
a grid printed on the sample may be dissipated in a combusted
manner in the heating stage of the sample. Thus, in a case of a hot
rolling, a grid may be composed by forming patterns or lines (e.g.,
a circular shape of a latticed shape) on the sample `S` by etching
so as to avoid the grid being dissipated due to the heat being
applied.
[0059] Once the sample `S` is formed with a grid it may be placed
at the fixing jig 10 as illustrated in FIG. 1. In a case of
obtaining a forming limit diagram while a hot rolling is being
performed, the sample `S` may be configured to go through a process
of being heated at or above about 900.degree. C. through a high
frequency heating coil `C`. At this time, in order for enhancing
the degree of precision of the test by having the temperature
gradient in between the sample `S` and the two jigs 10 and 20
minimized, the mobile jig 20 and the fixing jig 10 may be
pre-heated to about 200.degree. C. through the heaters 11 and 21.
In addition, the temperature of the punch 30 may be controlled
through the temperature controlling apparatus 33 so that the
temperature of the punch 30 may be maintained from about
-20.degree. C. to about a room temperature (e.g., about 20.degree.
C.).
[0060] When the heating process with respect to the sample is
completed, as illustrated in FIG. 2, the driving apparatus 40 may
be operated, and the mobile jig 20 is descended until the sample
`S` is completely fixed in between the fixing jig 10 and the mobile
jig 20. That is, as can be seen from FIG. 2, the driving plate 51
is lowered, and correspondingly, the mobile jig 20 is lowered. The
driving plate 51 may be lowered until the lower surface of the
driving plate 51 is in contact with the upper surface of the second
base 18. For example, the tester apparatus may be structured such
that the distance the driving plate 51 is lowered until the lower
surface of the driving plate 51 contacts the upper surface of the
second base 18 may be equivalent to the distance that the mobile
jig 20 is lowered until the fixing protrusion 20b disposed at the
lower surface of the mobile jig 20 is fixed in the fixing groove
10b disposed at the upper surface of the fixing jig 10. Further,
the camera unit 60 does not move and remains stationary, since it
is fixed to the lower portion of the fixing jig 10 via the
installation bracket 61.
[0061] After fixing the sample `S` between the fixing jig 10 and
the mobile jig 20, as illustrated in FIG. 3, the MTS is operated to
descend the punch 30, and the forming with respect to the sample
`S` is started. As can be seen from FIG. 3, as the punch 30 is
lowered, the guide rod 32 may be lowered into the guider 22. The
guide rod 32 may descend up to a distance equivalent to the length
of the guide hole 22a, however the tester apparatus may be
configured such that the punch 30 will come into contact with the
sample `S` before such a distance is traveled by the punch 30. As
can be seen from FIG. 3, once the punch 30 comes into contact with
the sample `S`, the sample `S` becomes deformed. Camera unit 60 may
capture images of the deforming of the sample `S` while the punch
30 exerts a force on the sample's'. Rod cell 31 may assist in the
control of the force exerted by the punch 30 by monitoring the
weight that is applied on the punch 30 by the mobile unit M2.
[0062] As illustrated in FIG. 4, the punch 30 may be descended
until the point in time when a break occurs at the sample `S`. The
point of time when a break occurs at the sample `S` may be
monitored through the camera unit 60, and when an occurrence of the
break of the sample `S` is found, the pressurization movement by
the MTS is stopped immediately.
[0063] Next, the mobile unit M2 of the MTS and the punch 30 are
moved backward by following the movements of the above in a reverse
order. That is, the mobile jig 20 may be ascended so that the
sample `S` may be retrieved and analyzed. By interpreting the
deformation of the grid formed on the sample `S` after the sample
`S` is separated from the jigs 10 and 20, the data with respect to
the major deformation rate and the minor deformation rate may be
calculated, and on the basis of the obtained deformation rate data,
the obtaining with respect to the forming limit diagram may finally
be achieved. For example, properties regarding a strain limit that
sample `S` may endure may be measured based on an analysis of the
deformation of the grid to obtain the forming limit diagram.
[0064] In a case of a cold rolling, the obtaining process of a
forming limit diagram may be similarly performed while the heating
process with respect to the sample and the jig are omitted from the
process above.
[0065] As shown in FIG. 5, a tester apparatus in accordance with
another embodiment of the present disclosure is shown.
[0066] The difference of the present embodiment from the earlier
embodiment is that an electric motor 43 may be used in place of the
hydraulic cylinder 41 of the driving apparatus 40.
[0067] That is, from the earlier embodiment, the hydraulic cylinder
41 may be replaced with the electric motor 43. The electric motor
43 may be composed of a servo motor that is capable of controlling
the number of rotations of the electric motor 43 and may be capable
of rotating backward and forward.
[0068] In addition, to decelerate the rotation movement generated
at the electric motor 43 and to boost the generated force, a
booster apparatus 44 may be installed in between the electric motor
43 and the driving plate 51. Here, the booster apparatus 44 may be
composed of a decelerating apparatus using a planetary gear.
[0069] According to the above described embodiments, a tester
apparatus for obtaining a forming limit diagram for a sample and a
method of operating the tester apparatus for obtaining a forming
limit diagram of the sample has been disclosed which is capable of
selectively performing a hot rolling and cold rolling test. The
test apparatus in accordance with the above-described embodiments
may include heaters disposed internally within the fixing jig and
mobile jig. During a hot rolling, the fixing jig and mobile jig may
be preheated to a predetermined temperature before the mobile jig
is lowered to fix the sample between the mobile jig and fixing jig.
The preheating of the mobile jig and fixing jig minimizes a
difference in temperature between the sample which may be heated up
to or above about 900.degree. C. and the mobile jig and fixing jig.
The tester apparatus includes a punch disposed at an upper side of
the mobile jig which is lowered to perform a forming on the sample.
The punch may include a guide rod disposed on one side of the punch
which extends from a lower surface of the punch. The guide rod may
be fitted within a guider which is disposed on an upper surface of
the mobile jig, to guide movement of the punch when the punch is
lowered. While the example embodiments disclosed herein have
illustrated a testing apparatus having a punch and mobile jig which
are moveable in a vertical direction, one of ordinary skill in the
art would understand that, if desired, the testing apparatus may be
modified or altered such that the configuration of the testing
apparatus is capable of moving the punch and the mobile jig in a
horizontal direction, or at an angle, to perform a forming on the
sample.
[0070] Although a few example embodiments of the present disclosure
have been shown and described, it would be appreciated by those
skilled in the art that changes may be made to these embodiments
without departing from the principles and spirit of the disclosure,
the scope of which is defined in the claims and their
equivalents.
* * * * *